Building owners are faced with the dual challenge of controlling energy consumption while safeguarding the health and well-being of building occupants. On the energy efficiency front, buildings account for 40% of all primary energy use and associated greenhouse gas (GHG) emissions, according to the US Department of Energy. Within commercial buildings, heating, ventilation, and air-conditioning (HVAC) systems historically consume 40% of total energy. This high cost represents an issue that is top of mind for building owners.
On the occupant health front, the emergence of highly contagious respiratory diseases (e.g., COVID-19, SARS, H1N1, MERS) has prompted facility managers and engineers to rethink HVAC designs. Efforts are directed at helping to reduce the spread of pathogens by purifying air, improving ventilation, and better managing airflows.
Building engineering design offices, and OEMs who build HVAC systems can contribute to achieving these dual end-user objectives by designing systems that prioritize both energy efficiency and occupant safety. One key technology that can simultaneously address both these concerns is the new generation IIoT-ready variable speed drives (VSDs).
Energy efficiency and health safety advantages of VSDs
The VSD is no longer just a shaft turner. VSDs can be used in buildings as connected products that provide ventilation system performance optimization and precision control, resulting in superior airflow and lower energy consumption.
Listed below are four ways both OEMs and end users can benefit from the integration of VSDs into HVAC systems:
- More directed airflows – Ducted HVAC systems can be configured to increase the rate of fresh air exchange (using filtered outside air) while reducing rates of recirculated indoor air to help lower the risk of pathogen spread. Instead of the traditional practice of shutting down ventilation systems overnight and on weekends (which halts air circulation), a VSD integrated HVAC system could run at low speed without interruption to increase the replacement of air, while consuming very little energy. Replacing traditional fixed-speed motor control products with VSDs provides facilities managers with the ability to adjust airflow settings based on building occupancy. In fact, with VSDs, regulation of ventilation systems can become a function of the number of people in a room. During office hours, facility teams can configure different rates of ventilation across the building, slowing down fan speeds where occupancy is low while increasing speeds when occupancy rates are high.
- Easier management and control – VSDs can either work in standalone mode or be managed by programmable logic controllers (PLCs) or building management systems (BMS). At Schneider Electric our VSD’s are pre-engineered in our BMS and come with communications and alerting functionality embedded called VSD Smart Widget. Also, they support BACnet, the main communications protocol used in buildings. They are also capable of monitoring connected devices, such as fans or motors, and can issue alerts when behavioral anomalies occur. For example, if a belt that drives a fan is not well tightened or if slippage is occurring, the VSD will send out an alert. Also, if a motor is overheating, information from sensors is communicated back via the VSD to the ventilation system operators. Using connected building solutions makes VSDs easy to integrate and decreases the number of individuals needed on-site for installation and operation.
- Lower energy consumption – Energy savings represent one of the biggest benefits of VSDs. According to the U.S. Department of Energy, VSDs can save up to 40% in energy consumption, when compared to fixed speed drives. Commercial building owners can experience payback periods of less than one year.
- Flexibility in addressing brownfield upgrade requirements – In addition to easily integrating into new-build HVAC building systems, in retrofit situations, VSDs can be used directly with simple air pressure sensors to regulate airflow without requiring external PLCs or other automation systems. An existing, older ventilation system can be upgraded without changing motors or fans using simple and compact HVAC VSD. VSDs can either be external to the air-handling unit or embedded inside. To overcome floor space constraints, the drive can also be cabinet or wall-mounted or even be mounted outside on the roof of the building. VSD solution configurations can be generated very easily, without the need of an expert, with EcoStruxure Industrial Device mobile application. Remote mobile solutions are decreasing the physical touch to products and the time spent on the field so the risk of transmission of the virus via product. If an existing BMS system is in place, our VSDs are capable to communicate with them with flexible communication protocols like LonWorks, BACnet, and Modbus.
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Schneider Electric field studies project that 20-30 percent of building owners have integrated VSDs into their ventilation systems, a percentage that we estimate will grow to 50-70 percent over the next few years. This represents an opportunity for the OEMs who configure and build these systems and for end users who can enjoy the health and energy-saving benefits.